Whoever is inaugurated as president Jan. 20 will, in the first year of his term, face a decision that will have a greater impact on the economy than any other single call he will make: Whom to select as chairman of the Federal Reserve.

Ben S. Bernanke’s term ends Jan. 31, 2014, about a year after the president takes office; if the past is a guide, and given the sluggishness of the Senate confirmation process, a nomination should happen by Labor Day.

That leaves a potential vacancy in a job that has become all the more difficult during Bernanke’s time in office. The Fed chairman has always been powerful, controlling the levers of the nation’s monetary policy. But now, since the Dodd-Frank legislation passed in 2010, the Fed and its leader have even more explicit power and responsibility to address risks in financial system and try to lessen the damage from future crises.